In the existing heat source system, a fan is one of the most commonly used heat-dissipating apparatuses. The conventional fan structure is composed of a housing, a hub, blades and a motor component, wherein screw holes are formed on four corners of the housing. When the heat source system uses the aforementioned fan structure as its heat-dissipating device, four screw fastening holes corresponding to the screw holes of the fan housing are generally formed on the heat source system, and then four pieces of screws are inserted into the screw fastening holes of the heat source system and into the corresponding screw holes of the fan housing, so as to fix the fan on the heat source system.
However, the assembly of the heat source system and the fan needs to use quite a lot of screws, and the expense of molding tools and material used for developing the housing portion in the conventional fan structure also occupies quite a large portion of the total fabrication cost of the fan, so that the cost for fabricating and assembling the conventional fan cannot be further lowered.
Further, when the conventional fan is in operation, big noise is frequently generated due to the air resistance therein. Although it is possible to lower slightly the noise level of the conventional fan by modifying the shape of the fan housing, yet the noise level thereof still cannot be lowered effectively.
Moreover, the air volume provided by the conventional fan is restricted by both the opening size of the fan housing and the dead space portion between the heat source system and the fan housing, so that the heat generated in the heat source system fails to be totally removed. Hence, with respect to the heat source system, the conventional fan cannot dissipate the heat completely therein, so that the problem of residual heat still remains.